The drivers noticed something suspicious and stopped to investigate. The remains they found had been wrapped in some sort of plastic material, but had been left out there for quite some time, Point Reyes National Seashore spokesman John Dell'Osso said.

Dell'Osso said that it remains unclear whether the remains were moved from another location. Also, the gender of the body is still unknown.

FBI investigators are expected to remove the remains sometime later this afternoon and will work with the Marin County Coroner to determine the victim's identity and cause of death, according to Dell'Osso.

Marin County sheriff's officials posted a message on Twitter that showed search and rescue teams combing the area for evidence related to the criminal investigation. There is no threat to the community, they stressed.